A new species ofCortinarius sectionBolares from Japan

Cortinarius reticulisporus sp. nov., found in deciduous forests, is described and illustrated. It closely resemblesCortinarius rubicundulusin its pileus color and the vivid yellowing of the context on bruising, but differs from the latter in its subglobose to broadly ellipsoid basidiospores with quotient of the length/width smaller than 1.4 and particularly fine lines connecting warts when observed under SEM. The differences betweenCortinarius reticulisporus and other similar taxa are briefly discussed.